The UN Security Council has unanimously adopted a resolution aimed at identifying those responsible for using chemical weapons in attacks in Syria that have killed and injured a growing number of civilians.

The UN Security Council has unanimously adopted a resolution aimed at identifying those responsible for using chemical weapons in attacks in Syria that have killed and injured a growing number of civilians.

While Russia and the US have failed to agree on a way to end the Syrian conflict, now in its fifth year, they have agreed on eliminating the country's chemical weapons.

The draft resolution fills a gap in assigning blame for chemical weapons attacks so the perpetrators can be brought to justice.

The Security Council vote came two days after US secretary of state John Kerry and Russian foreign minister Sergey Lavrov reached agreement on the final text of the resolution.

None of the 13 other council members raised objections.

A chemical weapon attack on a Damascus suburb killed hundreds of civilians on August 21 2013.

There have been numerous reports of continuing use of chemicals as weapons in Syria, especially chlorine-filled barrel bombs, since then.

"Pointing a finger matters," US ambassador Samantha Power told the council after the vote, praising members for taking "another step aimed at stopping the use of chemical weapons in Syria".

The Organisation for the Prohibition of Chemical Weapons (OPCW), the global chemical weapons watchdog, has a mandate to carry out fact-finding missions to determine whether chemical attacks occurred in Syria. But neither the organisation nor the United Nations has a mandate to determine responsibility.

The resolution asks UN secretary-general Ban Ki-moon, in co-ordination with the OPCW, to submit recommendations to establish a joint investigative mechanism.

The investigative body would identify those who are "perpetrators, organisers, sponsors or otherwise involved in the use of chemicals as weapons, including chlorine or any other toxic chemical" in Syria, in instances where an OPCW fact-finding mission determines that an incident involved, or was likely to have involved, their use.

In March, the council approved a US-drafted resolution that threatens measures, including sanctions, over the use of toxic chemicals as weapons in Syria.

The United States has been pressing for the council to ensure accountability for the growing number of alleged chlorine attacks in Syria, many reportedly using barrel bombs dropped from helicopters.

The US sponsored an informal Security Council meeting in April for council members to hear first-hand accounts of chemical weapons attacks. In early June, Syrian activists and doctors said chlorine had been increasingly used as a weapon. And in mid-July reports emerged that Islamic State, which controls about a third of Syria and Iraq, used projectile-delivered poison gas against Kurdish forces in both countries on several occasions in June.

Syria's declared stockpile of 1,300 metric tons of chemicals has been destroyed, but the OPCW is investigating possible undeclared chemical weapons.

Chlorine is not officially considered a warfare agent and was not among the chemicals declared by Syria, but its use as a weapon is illegal.